Benzophenone-3,4,3,4-tetracarboxylic acid diimides of 3,5-dialkyl-4- hydroxyphenyl substituted amines

ABSTRACT

Benzophenonetetracarboxylic acid diimides of 3,5-dialkyl-4hydroxphenylsubstituted amines of this invention effectively stabilize organic materials against the effects of heat and oxygen. The diimides of this invention are prepared by reacting the appropriate 3,5-dialkyl-4-hydroxyphenylsubstituted amine with benzophenone-3,4,3&#39;&#39;,4&#39;&#39;-tetracarboxylic acid dianhydride or diimide. An example of this class of stabilizers in N,N&#39;&#39;-bis(3,5di-t-butyl-4-hydroxybenzyl)3,4,3&#39;&#39;,4&#39;&#39;-tetracarboxylic aciddiimide.

United States Patent 1191 Dexter BENZOPHENONE-3,4,3,4-

TETRACARBOXYLIC ACID DIIMIDES OF 3,5-DIALKYL-4-HYDROXYPHENYLSUB- STITUTED AMINES [75] Inventor: Martin Dexter, Briarcliff Manor,

[73] Assignees Ciba-Geigy Corporation, Arclsley,

3,734,926. [52 11.5. C1. 266/451Ffi366/326 N 511 1m. (:1. C08f 45/58 [58] Field of Search 260/458 N [111 3,821,162 5] June 28, 1974 Primary Examiner-Melvyn I. Marquis BSIRACT Benzophenonetetracarboxylic acid diimides of 3,5 dialkyl-4-hydroxphenylsubstituted amines of this invention effectively stabilize organic materials against the effects of heat and oxygen. The diimides of this in vention are prepared by reacting the appropriate 3,5- dialkyl-4-hydroxyphenylsubstituted amine with benzophenom-3,4,3,4-tetracarboxylic acid dianhydride or diimide. An example of this class of stabilizers in N,N- '-bis(3,5-di-t-butyl-4-iiydroxybenzyl)3,4,3',4- v tetracarboxylic acid-diimide.

3 Claims, No Drawings 1 1 BENZOPHENONE-3,4,3,4-TETRACARBOXYLIC ACID DIIMIDES OF 3,5-DIALKYL-4-HYDROXYPHENYLSUBSTITUTED AMINES This application is a divisional application of US. application Ser. No. 186,560, filed on Oct. 4, 1971, now US. Pat. No. 3,734,926.

DETAILED DESCRIPTION This invention relates to novel benzophenone tetracarboxylic acid diimide derivatives of 3,5-dialkyl-4- hydroxyphenylsubstituted amines which are useful as stabilizers for organic polymeric materials which are subject to thermal and oxidative deterioration. The compounds of this invention are represented by the formula:

wherein each of R and R is the same or different (lower) alkyl group of from one to four carbon atoms; and

y has a value of from O to 3.

Illustrative examples of (lower) alkyl groups of from one to four carbon atoms which are represented by R and R are methyl, ethyl, propyl, isopropyl, butyl and can be prepared by reducing 3,5-dialkyl-4-hydroxyphe- I l a 1i R1 ii ll a t-butyl. The preferred groups are methyl, isopropyl and t-butyl.

The compounds of the formula 1 wherein y is 0, 2

and 3, can be prepared by reacting a 3,5-dialkyl-4- hydroxyphenylsubstituted amine of the formula 110- CH:N

R 3: III

wherein R and R are as defined previously and R is an alkyl group such as methyl or ethyl, with benzophenone- 3,4,3',4-tetracarboxylic acid diimide, in an inert solvent such as dimethyl forrnamide at approximately l20C.

nyl-propylnitrile with lithium aluminum hydride to yield the corresponding amine. The nitrile can be prepared according to the method described in US. Pat' No. 3,121,732 wherein the appropriate dialkylhydroxy phenol is reacted with acrylonitrile. The 3,5-dialkyl-4- hydroxybenzyl dialkyl amine of formula III can be prepared as described by E. P. Previc et al., Industrial and Engineering Chemistry, Vol. 53, No. 6, Page 469, June The is'eri'zabfierwae sj iis'zs'laaariiaiyiiazeta"aiimide can be prepared by methods described in US. Pat. No. 3,275,651.

The compounds of this invention are stabilizers of organic polymeric material normally subject to thermal and oxidative deterioration. Materials which are thus stabilized include synthetic organic polymeric substances such as vinyl resins formed from the polymer- Eization of vinyl halides or from the copolymerization of .vinyl halides with unsaturated polymerizable compounds, e.g., vinylesters, mil-unsaturated ketones,v

ozfi-unsaturated aldehydes, and unsaturated hydrocarbons such as butadienes and styrene; poly-a-olefins such as polyethylene, polypropylene, polybutylene, and the like, including copolymers of poly-a-olefins; polyurethanes and polyamides such as poly-hexamethylene adipamide and polycaprolactam; polyesters such as polyethylene terephthalate; polycarbonates', polyacetals; polystyrene; polyethyleneoxide; polyisoprene; polybutadene; and copolymers such as those of high impact polystyrene containing copolymers of butadiene and styrene and those formed by the copolymerization of acrylonitrile, butadiene and/or styrene.

In general, one or more of the stabilizers of the present invention are employed in amounts, in toto, of from about 0.005 to about 5 percent by weight of the composition to be stabilized. A particularly advantageous range of the present stabilizers is from about 0.05 percent to about 2 percent. The preferred range is particularly effective in polyolefins such as polypropylene and polyethylene. I

These compounds may be incorporated in the polymer substance during the usual processing operations, for example, by hot-milling, extrusion compounding and the like. The polymers may be produced as films, fibers, filaments, hollow-spheres and the like, The heat stabilizing properties of these compounds advantageously stabilize the polymer against degradation during such processing at the high temperatures generally encountered.

The stabilizers employed in this invention can also be used in combination with other stabilizers or additives. Especially useful co-stabilizers are dilauryl-B-thiodipropionate' and distearyl-B-thiodipropionate.

The following fonnula represents co-stabilizers which are in certain instances very useful in combination with the stabilizers of this invention:

wherein R isan alkyl iotibi'iavifig frorh six to 24 carbon atoms; and m is an integer from 1 to 6. The above co-stabilizers are used in the amount of from 0.01 to 2 percent by weight of the organic material, and preferably from 0.1 to 1 percent.

Other antioxidants, antiozonants, thermal stabilizers, ultraviolet light absorbers, coloring materials, dyes, pigments, metal chelating agents, etc., may also be used in the compositions in combination with the stabilizers of the invention.

The following are presented to further illustrate the present invention without introducing any limitation thereto.

EXAMPLE 1 N,N'-Bis( 3 ,5-di-t-butyl-4-hydroxybenzyl)Benzophenone-3,4,3,4 tetracarboxylic acid diimide To 200 m1. of dimethylformamide were mixed 16.0 g of benzophenone-3,4,3,4-tetracarboxylic acid diimide (0.05 mole) and 27.6 g of 3,5-di-t-butyl-4- hydroxybenzyl dimethyl amine (0.1 mole). The reaction mixture was heated under a nitrogen atmosphere at 120C to 125C for 6 hours. After cooling, the reaction mixture was poured into water. The material obtained was extracted with ether. The ether extract was washed with dilute HCl and then with water. Upon evaporation of the ether, an amorphous solid was obtained. The product was triturated with hot petroleum ether after which it was recrystallized twice from aqueous acetone. The product obtained has a melting point of218 to 221C.

Analysis for C H N O Calculated: C, 74.58; H, 6.93; N,3.70

% Found: C, 74.34; H,6.89; N354 In a similar manner, by substituting 3-methyl-5-tbutyl-4-hydroxybenzyl-dimethyl amine for 3,5-di-tbutyl-4-hydroxybenzy1-dimethyl amine there is obtained N,N-bis-(3-methyl-5-t-butyl-4-hydroxybenzyl)- benzophenone 3,4.3',4 tetracarboxylic acid diimide.

EXAMPLE 3 N,N '-Bis( 3 ,5-di-t-butyl-4-hydroxyphenyl) benzophenone-3,4,3',4'-tetracarboxylic acid diimide The reaction flask is charged with l 1.05 g (0.05 moles) of 4-amino-2,6-di-t-butylphenol, 8.0 g (0.025 mole) of benzophenone-3,4,3',4'-tetracarboxylic acid dianhydride and 100 ml of -dichlorobenzene. The reaction mixture is heated to reflux until the imidization is completed. After cooling, the mixture is filtered and washed with petroleum ether. The filtrate is dried and recrystallized from aqueous acetone acid and filtered, after which it is washed with acetic acid and dried.

By substituting an equivalent amount of ,B-(3,5-di-tresponding N,N'-bis butyl-4-hydroxyphenylethyl)amine for 3,5-di-t-butyl-4- EXAMPLE 4 Unstabilized polypropylene powder (Hercules Profax 6501) was thoroughly blended with 0.2 percent by weight of N,N-bis(3,5-di-t-butyl-4- hydroxylbenzyl)benzophenone-3,4,3',4- tetracarboxylic diimide.

Also prepared were samples of polypropylene containing 0.1 percent by weight of the same stabilizer and 0.3 percent by weight of distearylthiodipropionate (D- STDP). The blended materials were then milled on a two-roll mill at 182 C for 10 minutes, after which time the stabilized polypropylene was sheeted from the mill and allowed to cool.

The milled polypropylene sheets were then cut into pieces and pressed for 7 minutes on a hydraulic press at 218 C, 2,000 pounds per square inch pressure. The resulting sheets of 25 mil thickness were tested for resistance to accelerated aging in a forced draft oven at 150 C. The results are set out in Table 1 below:

TABLE 1 Oven Aging At 150" Additive(s) Hours to Failure 0.2% of N,N'-bis(3,5,di-tbutyl-4-hyd roxybenzyl )benzophenom-3,4,3.4'-tetracarboxylic acid diimide 50 0.1% of N,N-bis(3,5-di-t-butyl- 4-hydroxybenzyl)benzophenone-3,

4,3 ,4'-tetracarboxylic acid diimide 0.3% DSTDP 2070 Unstabilized Polypropylene 3 0.3% DSTDP alone 20 "distenrylthiodipropionatc (a synergist for phenolic antioxidants) The above data clearly indicates the significant increase in the stabilization of polypropylene upon addi tion of the antioxidants of the present invention.

Stabilized polypropylene compositions are also obrained when 0.5 percent of N,N'-bis[3-(3,5-di-t-buty1- 4-hydroxyphenyl)propyl]benzophenone-3,4,3',4'- tetracarboxylic acid diimide,' N,N'-bis(3-methyl-.5-tbutyl-4-hydroxybenzyl )benzophenone-3 ,4,3 ',4 tetracarboxylic acid diimide N,N'-bis(3,5-di-t-buty1-4- hydroxyphenyl 3,4'-tetracarboxylic acid diimide respectively are employed alone or in combination with DSTDP.

EXAMPLE 5 Pellets (500 g) of unstabilized nylon-6,6 (Zytel 101, Dupont) are placed in a Kitchen Aid Mixer. With mixing a solution of 2.5 g (0.5 percent) of N,N-bis(3,5-dit-butyl-4-hydroxyphenyl )benzophenone-3 ,4,3 ',4 tetracarboxylic acid diimide in 20 ml of acetone is added slowly to the nylon pellets. The stabilized pellets are dried at C at 1mm for 4 hours.

The polyamide formulation is extruded at 600F thr- 7 and maintained at 350 psi for 2 to 3 minutes.

The stabilized polyamide has better viscosity, color reough a A inch die into a rod which is water cooled and and finally t Constant g' Under g Vacuum chopped into pellets. A inch Brabender extruder, at equipped with a nylon screw, is used. The pellets are The dried rubber g) is heated uhdel' hhl'ogeh at dried at 80 at lmm for 4 hours. 125 in a Brabender mixer and to this is added with The dried pellets are pressed into inches X 5 inches 5 mixing (H25 8 P of l x 0.005 inch films at 290 and 350 psi for 3 minutes. y yp )p p h The mold is transferred quickly to a water-cooled press .3, -tetracarb xylic acid diimide. The composition is mixed for 5 minutes after which it is cooled and S l (2,2 'df c p s i idid d 165.65 compression molded at 125 C into 5 inches X 5 inches films are aged in an air circulating rotary oven at 150C 10 X (1025 iheh P q for various time periods. The viscosity of a ll percent The P q are Placed on aluminum Sheets and f i id l ti f d d unaged polymer heated in a circulating air oven at 100 C for up to 96 pies are determined at 25C. Stabilizer effectiveness is hours- The Viscosity of a Pereeht toluene sehhioh judged by the percent retention of specific viscosity, of g and uhaged rubber samples are determined at color-formation, and weight retention after oven aging. Stabilizer effectiveness is judged y the Pereeht retention of specific viscosity, color formation and gel tention, and substantially less weight loss than a polycement after Oven g- The stabilized rubber has amide which is unstabilized aft r v a i ter viscosity, color retention and less gel content than Stabilized polyamide compositions are prepared in a the rubber which is Unstabihled after Oven agingsimilar manner as above with the following stabilizers: Similar results are Obtained when butyl-4-hydroxybenzyl )benzophenone-3 ,4,3 ,4-

a. 0.5 percent of N,N'-bis(3,5-di-t-butyl-4-. tetracarboxylic acid diimide is used in .place of the hydroxybenzyl)benzoph non -3,4,3,4- above mentioned stabilizer in the rubber composition.

tetracarboxylic acid diimide b. 0.5 percent of N,N-bis(3-methyl-4-t-butyl-4- hydroxybenzyl)benzophenone-3,4,3,4- EXAMPLE 7 tetracarboxylic acid diimide 2-..-

c. 0.5 percent of N,N'-bis[2-(3,5-di-t-butyl-4- comprisinglinear polyethhydroxypheny)ethyl]benzophenone-3,4,3,4'- ylene and 0.1% by weight of N,N'-bis(3,5-di-t-butyl-4- tetracarboxylic acid diimide. hydroxybenzyl)benzophenone-3,4,3,4-

tetracarboxylic acid diimide. This composition resists EXAMPLE 6 discoloration at 120 C longer than one which does not A quantity of SBR emulsion containing 100 g of rubcontain the stabilizer. her (500 ml of cold SBR type 1500) previously stored What iS Claimed i I under nitrogen, is placed in a beaker and stirred vigorl. A composition of matter stabilized against oxidaously. The pH of the emulsion is adjusted to 10.5-with tive deterioration which comprises an organic polya 0.5N NaOH solution. meric material normally subject to oxidative deterio- To the emulsion is added ml of 25%NaCl soluration containing from 0.005 to 5 percent by weight of tion. A 6% NaCl solution which has been acidified with a stabilizing compound of the f rm l HCl to H 1.5 is added in a thin stream with vigorous wherein stirring. When pH 6.5 is reached, the rubber begins to 50 each of R and R is the same or different (lower) coagulate and the addition is slowed down in order to alkyl group of from one to four carbon atoms; and maintain uniform agitation. The addition of the acidic 6% NaCl solution is tenninated when a pH 3.5 is reach- I y has a value of from 0 to 3. ed. The coagulated crumb-rubber slurry at pH 3.5 is 2. The composition of claim 1 wherein R and R is stirred for one-half hour. 55 tertiary butyl or methyl.

The coagulated rubber is isolated by filtration 3. The composition of claim 2 wherein the stabilizing through cheese cloth. and rinsed with distilled water. compound is N,N-bis-3,5-di-t-butyl-4- After three subsequent washings with fresh distilled wahydroxybenzyl)benzophenone-3,4,3',4'-

ter. the coagulated rubber is dried. first at 25 mm Hg tetracarboxylic acid diimide. 

2. The composition of claim 1 wherein R1 and R2 is tertiary butyl or methyl.
 3. The composition of claim 2 wherein the stabilizing compound is N,N''-bis-3,5-di-t-butyl-4-hydroxybenzyl)benzophenone-3,4,3'', 4''-tetracarboxylic acid diimide. 